Centrifugal separator



April 21, 1959 F. G. SANCHEZ 2,883,054

CENTRIFUGAL SEPARATOR Filed Feb. 4, 1955 IN VENT 0R.

505060 6. JAM/1E2 BY v m (R). @M 3 United States Patent i CENTRIFUGALSEPARATOR Federico G. Sanchez, Havana, Cuba Application February 4,1955, Serial No. 486,114

5 Claims. (Cl. 21085) This invention is concerned generally withcentrifugal separators, and more specifically with improvements forcentrifugal separators of a type that are particularly adaptable for usein the sugar industry.

In separating raw sugar magma, it is usual for the process to include awashing and separating of the magma to obtain two liquid products andsolid sugar crystals. In such separation, there have been variousdifiiculties encountered which exist in the heretofore known separatorsthat have been employed in the sugar industry. Among such diificultiesis the fact that an incomplete separation of the liquids from the solidcrystals of sugar is apt to exist. Also, there is some loss of the syrupby creepage in the vicinity of the widest diameter, or extremity, of theseparator centrifugal element.

Furthermore, another difliculty has been the inability to observe theseparation during the action of actual separation, as the machine isoperating. This has been due to the type of construction of separatorsas heretofore employed and creates a real difliculty in optimum controlof the separation process.

Other difficulties encountered have been the return of some of theseparated solids back into the centrifuge, because of air turbulencenear the extremity of the centrifuge. Also, it has been necessaryheretofore to employ a dissolving tank, for use in the afiinationprocess, which makes use of the sugar crystals dissolved in water.

Consequently, it is an object of this invention to provide an improvedcentrifugal separator that includes means for overcoming the variousdifficulties indicated above.

Another object of this invention is to provide vanes attached to therotating purging cone of the separator and situated to cause anextraction-fan action that will cause a local forced air flow throughthe purging cone and into the various collector sections of theseparator.

Another object of this invention is to provide circumferentially-locatedspacers or ribs, for supporting the screen on the purging cone. Thescreen is thus substantially separated from the entirely perforatedsurface of-the cone. Consequently, the flow of liquid through thepurging screen and through the perforations of the purging cone will beevenly distributed over the entire surface of the purging cone. In thisway no clogging or backing up of the purging liquid, after having passedthrough the screen, will occur. At least not to an extent which couldcause a blocking of the flow of liquid through the purging cone wherebyincomplete purging of the liquids from the solid sugar crystals would behad. v Another object of this invention is to provide a frustoconicalair duct which cooperates with the purging cone and the final collectorfor the sugar crystals so as to allow a free passage of intake air whichmay be then distributed evenly over the entire surface of the cone. Inaddition, the use of an air duct of this type renders Patented Apr. 21,1959 2 the inside of the purging cone freely visible so that the actionof the separator may be observed at all times.

Anotherobject of this invention is the provision of adjustable spraynozzles for. directing washing spray against the inner surface of thepurging cone. Such adjustable nozzles being not only adjustable inuniversal manner for the individual nozzles but in addition being bodilyadjustable longitudinally parallel to the axis of the purging cone. Suchadjustable nozzles render the separator much more versatile in thatadjustments may be made for different materials being purged.

Another object of this invention is the use of a spray pipe forintroducing hot water to dissolve the sugar crystals after they areseparated, while they are still within the collector compartment of theseparator. By this means the use of dissolving tanks may be eliminatedand their cost saved, in addition to the time which is saved over thatnecessary for the dissolving of the sugar crystals in tanks. This samespray pipe may be used in different ways when different processes areemployed. For example, it may be desirable to blow in hot air for dryingthe sugar crystals, or in some cases, hot molasses may be introduced formaking new magma.

Other objects include provision for an overlapping disc to act as a sealfor preventing contamination of the separated solid crystals by any ofthe purged liquid, as well as the provision of access doors into thefinal collector compartment for observation of the separation action inthis compartment as well as for cleaning operations.

Briefly, the invention is concerned with the improvement in acentrifugal separator for use with sugar magma or the like whichcomprises a centrifugal purging member for separating solid crystalsfrom the liquids of the magma in which such purging member has aplurality of vanes thereon for forcing air to circulate through themember in the direction of the liquid flow therethrough. Similarly, theinvention also concerns an improvement in the centrifugal separator foruse with sugar magma or the like which comprises a purging cone forseparating solid crystals from the liquid, said purging cone beingrotated with its axis substantially horizontal and including aperforated supporting surface. The purging cone also includescircumferential ribs included on said supporting surface for supportinga purging screen which is separated therefrom; the ribs being also fordistributing the flow of purging liquid evenly over the surface of saidsupporting surface.

These and other objects and principles of the invention are set forth ingreater detail belowand are illustrated in the drawings, in which:

Fig. 1 is a partial cross-sectional view showing the elements of aseparator according to this invention; and

Fig. 2 shows a detailed view taken along the line 2-2 and looking in thedirection of the arrows, to show the location of the vanes relative tothe purging cone of the separator.

The various elements and features according to this invention may bestbe described in connection with the entire separator as illustrated inthe drawings and by describing the various elements thereof and theirrelated functions.

The separator includes a generally cylindrical housing 11, having anopening at the bottom like an inverted U, which is divided into twocompartments 12- and 13 on the interior thereof. The compartment 12 isthe first col lector section of the separator and includes an outercircular end panel 14 which is securely attached to, or may be formedof, a continuous part of the housing 11. The panel 14 is generallycircular in shape and lies in a plane that is perpendicular to the axisof the rotating parts of the separator."

The other wall of the accumulator compartment 12 is formed by a circularpartition 15 which is located inside the housing 11 and lies parallel tothe panel 14. The partition 15 also forms one wall of the compartment13, which is an accumulator section for a second stage or quality ofseparated liquids, and which has as its other enclosing wall an outerpanel 16 that is attached to the housing 11 (and in fact forms one endthereof).

It will be appreciated that there are convenient exhaust ducts oropenings (not shown) located in each of the accumulator compartments 12and 13 for drawing olf the separated liquids.

The stationary portion of the separator includes in addition to thehousing 11 an accumulator section 19, which is formed by a rounded sheetof housing material 20, that is attached firmly to the housing 11 bymeans of a plurality of struts 21. These struts 21 may be attached inany convenient manner to the material 20 of the accumulator section 19,as by means of welding, illustrated, and will be fastened to the housing11 of the separator in a detachable manner such as by means of bolts asillustrated.

The housing material 20 includes a fiat circular end disc portion 22having at least two access holes 23 and 24 therein for observing theaction within accumulator compartment 19, as well as for access withinthe compartment, for cleaning, etc. There are doors or closing panels(not shown) over these holes 23 and 24 to keep the separated crystals orother material from dying out, when the holes are not in use. Within thehousing material 20, and forming one boundary for the accumulatorsection 19, there is a frustoconical duct 27 which is securely attached,e.g. by welding, to become an integral part of the end portion 22 of thehousing material 20. This construction is such that the duct 27 leavesan unobstructed opening 28 at the small diameter end thereof, for theentrance of air as it is forced to circulate through the separator. Theother end of this frusto-conical duct 27 is also open, and is locatedjust inside of the extremity, or discharge end, of a purging conestructure 29. In this manner, the air which is drawn through theseparator is guided to, and evenly distributed over, the entire purgingsurface of the purging cone structure 29.

The purging cone structure 29 includes as support therefor a rotatableshaft 32, which has firmly attached thereon, as by welding illustrated,a disc 33. Disc 33 has fastened thereto an outer supporting collarmember 34 by means of any convenient attachment that is sufiicientlystrong and secure, such as a ring of bolts like bolt 35 illustrated. Thecollar member 34 has an angled extremity 36 to which is attached aconical sheet of material 37 that acts as the supporting surface for apurging screen 38, which is situated parallel to the conical surface 37.It will be observed that conical surface 37 is perforated over itsentire effective surface, having holes 39 therethrough to allow theliquids as separated to .pass through the surface 37 via the holes 39. Adisc 43 is securely fastened to the outer extremity of the conical sheetmaterial 37. At the inner edge of the screen 38, it is securely clampedin place by means of a clamping ring 44 that is drawn tightly over thescreen to clamp it by means of a series of bolts as illustrated.Separating the screen 38 from the perforated conical sheet material 37and supporting the screen, there is a series of ribs or rings 45 whichare located circumferentially relative to the purging cone 2'9 and whichare securely attached in an integral manner to the conical sheetmaterial 37.

To maintain a separation between compartments 12 and 13, there is asolid disc 48 that is securely attached as by welding to the supportingsheet material cone 37, and that has attached at its outer edge a solidfrusto-conical panel or partition 49. On the outside of panel 49, atabout the midpoint thereon, there is a flange '50 which is 4 situatedadjacent to the partition 15 and overlaps the inner circular boundary ofpartition 15.

Attached to the panel 49, as well as to the conical sheet material 37,there is a plurality of vanes 51 which are set at an angle of aboutforty-five degrees to the axis of the shaft 32 and the entire separator,in order to act as fan blades for drawing air (as introduced via theduct 27) through the purging cone 29 and into the accumulatorcompartment 12, so as to aid the purging action of the purging cone 29.A detailed view illustrating the situation of vanes like vanes 51, ishad in Fig. 2 in connection with a similar set of vanes located furtherout on the purging cone 29.

For providing the same local forced draft action in accumulatorcompartment 13, as was had by reason of the vanes 51 in accumulatorcompartment 12, there is a set of vanes 54, which may also be viewed inFig. 2 and which are attached to a panel 55 that is similar to the panel49 in connection with the vanes 51. It will be observed that the vanes54 extend beyond the outer edge of the panel 55 to increase the forcedcirculation or fan action with regard to air flow through the purgingcone 29 and into the accumulator section 13 to be expelled therefrom. atthe exhaust opening.

In connection with the accumulator compartment 13 there is an additionalset of small vanes 56 which are located on the outside of the panel 55and are set at an angle of about forty-five degrees to the axis of theseparator, similarly to the vanes 54. This may be readily observed inFig. 2. The action of auxiliary vanes 56 is such that air is forciblydrawn in around the inner edge of panel 16 (which forms one end of thehousing 11). In this way, any creepage of liquid, which has been purgedfrom the sugar crystals at the purging cone 29, is entirely avoided sothat any loss in this manner is obviated.

Also, another and more harmful result of creepage of the liquid fromaccumulator compartment 13, which is avoided, is that of thecontamination of the solid sugar crystals by having some of the purgedliquid drops creep out to the extremity where they might be thrown intothe final accumulator section 19. Such contamination action is furtheravoided or insured against by reason of a solid disc 57 which isattached to the outside of the panel 55 and overlaps the lower edge ofpanel 16 of the housing.

Within the purging cone 29, and adjustably there located, there is agroup of spray nozzles 61. Nozzles 61 are situated to discharge awashing liquid, e.g. water, against the screen 38, as the purging cone29 is rotated. Any desired number of these nozzles may be located arounda circular pipe 62 which has short nipple exten-. sions 63, one for eachnozzle 61. The nozzles 61 are held in the nipples 63 by means of aball-and-socket joint arrangement, in order to be able to adjust thedirection of flow from the nozzle as desired. There may be anyconvenient number of nozzles around the entire circle of the pipe 62,but it has been found entirely satisfactory to use six of these nozzles.It is contemplated that the nozzles 61 will be set to direct their sprayin a direction that is against the direction of rotation of the purgingcone 29. It is to be noted that with the construction illustrated, thepurging cone 29 will be rotated clockwise when viewed from the opening28 of the machine, i.e. the upper half of the cone 29 will be rotatingaway from the viewer when viewed as illustrated in Fig. l.

The water supply for the nozzles may be any convenient arrangement suchas a flexible hose '(not shown) that is connected to the pipe 62. Pipe62 is supported in the position illustrated by means of a number of arms64 which have clamps 65 at the end thereof for securely holding the pipe62. The arms 64 are attached integrally to a circular band 66 which alsohas triangular braces 67 attached thereto for adding stability to thesupport of arms '64. The pipe 62 and nozzles '61 thereon maybe bodilyadjusted in position, longitudinally along the s an. W

of the separator, by means of sliding the band 66 back and forth ascontrolled by a rod 70 which has a convenient attaching buckle or thelike, such as a U-shaped buckle 71 for attaching the rod 70 to the band66 by means of a pin coupling fastened through the triangular brace 67.At the outer extremity of the rod 70 there is a knob 72 and also asupporting lug 73 which has a set screw 74 therein to fix the positionof the rod 70.

Lug 73 and a similar lug 75, which slidably support the rod 70, are eachattached securely to the outside of a hot water jacket 77. Jacket 77surrounds an intake pipe 78 through which the magma or other material tobe separated, is fed. Within the pipe 78 there is a screw-fed mechanismwhich includes a rod 79 having a thin flange 80 that is shaped in aspiral around the rod 79 and attached thereto in the usual manner forproviding a screwfeed. This screw-feed carries material along the insideof the pipe 78, which has a circular cross-section. The jacket 77 iswatertight and provides a chamber surrounding the pipe 78 wherein hotwater 81 will be contained in order to keep the magma to a desired hightemperature for softening the same. At the center of the purging cone29, there is a pair of distributing cones 84 and 85 which are made ofimperforate material and which have their conical surfaces tapered inopposite directions. The inner cone 84 has a closed back 86 that isintegral with the conical portion 84 and that has a hole at the centerthereof for accommodating a small diameter threaded extension 87, of theshaft 32. Thus the inner distributing cone 84 is securely attached tothe extremity 87 of the shaft 32 by means of a nut and washer asillustrated.

The outer distributing cone 85 is faced in the opposite direction fromcone 84 and has a closed end formed by a disc 88 integrally attached tothe small end of the cone 85. The disc 88 has a hole 83 therein forpermitting entry of the feed-pipe 78 therethrough. The cone 85 isattached to rotate with the shaft 32 in any convenient manner, e.g. bymeans of a disc 89 that is keyed to a reduced portion 93 of the shaft 32by means of a key 90 which is shaped to also act as a spacer betweendisc 89 and the back 86 of the inside distributing cone 84. Cone 85 isthen attached to the disc 89 for rotation therewith by means of aring-shaped bracket 91 that is integrally fastened to the cone 85. Thereis a substantial amount of space to allow an exit for passage of thematerial to be separated, such as an opening 92 illustrated. The bracket91 is attached to the disc 89 by means of bolts as illustrated. It willbe observed that the disc 89 has a hole at the center thereof which fitsslidably over the reduced portion 93 near the extremity of the shaft 32.There is, of course, a keyway notch in the hole at the center of disc89, to accommodate the key 90.

Located centrally within the accumulator section 19 there is an invertedU-shaped pipe 95 which has a series of holes 96 therethrough on theouter periphery of the pipe 95. Pipe 95 may be supported in anyconvenient manner (not shown) and will have a desired fluid introducedtherein to be sprayed out through the holes 96 so as to contact thepurged sugar or other material, for any desired purpose such as todissolve the sugar when using an aflination process. In some instances,the pipe 95 may carry hot air under pressure so that the air will beblown over the purged sugar to dry the same. Or, in some operations, hotmolasses may be blown through the pipe 95 when a new magma is desired,e.g. for further purging in another centrifugal.

Operation In operation, the separator takes material to be separated,e.g. sugar magma, which is introduced into the feedpipe 78 and feeds itout by means of the screw-feed 79 to the end of the pipe 78. In leavingfeedpipe 78 it falls against the inside of cone 84, which is rotating atthe desired high speed along with the shaft 32. The

magma thus is partially distributed over the inner surface of cone 84and flows out oif the edge of the widest-pop tion of cone 84 intocontact with the inside of the second distributing cone 85. The materialis kept within cone by reason of the closed end disc 88 and flows in theopposite direction out along the inside of cone 85 until it isdischarged off the edge of the widest end of the cone 85 (throughopenings 92). It is then carried back in the opposite direction again bythe ring 44 and out on to the screen 38 of the purging cone 29.

As it continues to flow outward along the screen 38, liquid is forcedthrough the screen and into the hollow spaces between thecircumferential ribs 45, from where it is discharged through theperforation holes 39 of the sheet material cone 37. This action is aidedby air flowing in through the opening 28 and the diverging duct 27 tothe inside of purging cone 29, and then through the screen 38 and spacesbetween the ribs 45 to and through the perforation holes 39, all byreason of centrifugal force and of the air extracting action caused byvanes 51 and 54.

At a desired location along the purging cone 29, washwater is introducedfrom the nozzles 61 and the material continues to flow outward along thescreen 38 while liquid is extracted by reason of the centrifugal forceand flows out as just described.

After a predetermined distance along the screen 38, i.e. when the disc48 is passed, the liquids that are extracted from the material will flowinto the second accumulation chamber 13. The action here is the same asbefore in connection with the accumulator chamber 12, and in aid of thisliquid flow into the chamber 13 there is the set of vanes 54 which drawair through the purging cone 29. In addition to the vanes 54 small vanes56, located above the panel 55, create a fanning action to draw air inaround the panel 16 so as to keep any liquids contained in theaccumulator chamber 13 from creeping out of this opening.

Finally, the solid sugar crystals, or other purged material, will beejected over the extremity of the purging cone 29, i.e. this solidmaterial will fall away beyond the outer edge of disc 43 and be caughtin the final accumulator section 19. Here the solid material is treatedby spray which is ejected from the pipe through its holes 96, and thenthe material is carried out via a duct or other opening (not shown) asit leaves the separator.

It will be noted that during the course of this separation action, or atany desired time, the longitudinal position of the pipe 62 (whichcarries spray nozzles 61) may be adjusted axially of the purging cone29, by loosening the set screw 74 and grasping the knob 72 to slide therod 70 in or out through the supporting lug 73. This will slidablyadjust the position of the band 66, which supports the pipe 62 carryingthe nozzles 61.

While a specific embodiment of the invention has been described in somedetail in accordance with the applicable statutes, this is not to betaken as in any way limiting the invention, but merely as beingdescriptive thereof.

It is claimed:

1. In a centrifugal separator for use with sugar magma or the like, theimprovement comprising a purging cone for separating solid crystals fromthe liquid, said cone lying with its axis substantially horizontal, acollector for receiving solids from the widest end of said purging cone,said collector having a rounded peripheral configuration, and a spraypipe located near the periphery of said collector and centrally of saidrounded configuration for spraying said solids while in said collectorto eliminate the need of a dissolving tank.

2. An improved centrifugal separator for use with sugar magma or thelike comprising a purging cone for separating the liquids from thesolids, at least three accumulator sections adjacent to said cone forreceiving separated materials, at least two sets of vanes on said coneextending into said accumulator sections for drawing air through saidcone in aid of the dew of liquid therethrough, a third set of vanes fordrawing a separate stream of air into the last liquid accumulator at theexternal joint thereof to prevent -creepa-ge of liquid out of theaccumulator, circumferential ribs spaced axially apart on said purgingcone to spread the accumulation of liquid being purged evenly over thewhole cone, a frusto-conical air duct extending from the exterior ofsaid separator to the interior of said purging cone for supplying airand for leaving clear visual access thereto, and a set of spray nozzleswithin said purging cone, adjustable in direction and movable axially ofthe purging cone.

3. In a centrifugal separator having a feed pipe arrangement for usewith sugar magma or the like, the improvement comprising a purging conefor separating solid crystals from the liquid, said purging cone havinga plurality of vanes on the outside thereof for forcing air to flowthrough the cone in the direction of the liquid flow therethrough, and afrusto-conical air intake duct having open ends, the larger of said endsextending adjacent to the discharge extremity of said purging cone, thesmaller of said ends being unobstructed for inspection of the interiorof the separator at alltimes and allowing ready insertion or withdrawalof the feed pipe arrangement,

4. In a continuous action centrifugal separator for use with sugar magmaor the like, said separator having a horizontally mounted frusto conicalpurging cone surrounded by two separate collector chambers, theimprovement comprising a plurality of fan action blades extendingradially "into each of said collector chambers and mounted on said conefor rotation therewith, apartition separating said chambers and lyingtransversely of the axis of said cone, and 'imperforate annular meansattached to said cone and extending radially from the surface of thecone in overlapping relation with said partition to maintain goodseparation between said chambers.

5. In a continuous action centrifugal separator for use with sugar magmaor the like, said separator having a horizontally mounted fmsto conicalpurging conesun rounded by two separate collector chambers and includingan accumulator chamber located at the discharge end of said cone, theimprovement comprising a plurality of fan action blades extendingradially into each of said collector chambers and mounted on said conefor rotation therewith, a partition separating said collector chambersand lying transversely of the axis of said cone, first imperforateannular means attached to said cone and extending radially inoverlapping relation with said partition for separating said chambers,second imperforate annular means extending radially outward from saiddischarge end of the cone in close proximity to a wall of one of saidcollector chambers, and a plurality of relatively small fan actionblades rotating with said cone and located close to said wall of saidcollector chamber for drawing air into said chamber to prevent escape bycreepage of any purging liquid.

References Cited in the file of this patent UNITED STATES PATENTS830,230 Hofibauer Sept. 4, 1906 1,540,917 Appel June 9, 1925 1,581,089Roberts Apr. 13, 1926 1,714,232 Morris May 21, 1929 1,832,269 Webb Nov.17, 1931 1,902,982 Abbott Mar. 28, 1933 2,025,282 Hoffman et al Dec. 24,1935 2,028,168 Roberts Jan. 21, 1936 2,037,840 Weston Apr. '21, 19362,096,594 Sanchez Oct. 19, 1937 2,254,455 Sorenson Sept. 2, 19412,328,394- Neuman Aug. 31, 1943 2,720,982 Stuart Oct. 18, 1955 FOREIGNPATENTS 638,799 Great Britain June 14, 1950

